Please create an account to participate in the Slashdot moderation system


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 internet speed test! ×

Comment We've already seen this play out three times (Score 1) 70

First with music stores (e.g. Tower Records), then with video stores (mostly rental - e.g Blockbuster), then bookstores (B Dalton, Crown Books, Walenbooks). Frankly I'm surprised a brick and mortar video game store managed to hold out this long, given that that media was acknowledged as software to begin with. Music, movie, and book publishers mistakenly thought they were selling a physical product, and it took Internet piracy to make them realize they were selling software - a virtual product. There was no such misconception with video games.

Comment Did he check the math? (Score 1) 124

Centripital force is

F = mv^2/r

or a = v^2/r

At a typical takeoff speed of 150 knots, the lateral acceleration needed to keep the plane centered on a round runway with a 1.5km radius is 3.97 m/s^2, or 0.40g. On a freeway you'd just tilt the roadway based on the expected transit speed (about 24 degrees for 0.40g). But with a circular runway, planes are going to be traversing every part of it at all speeds from 0 to 150 knots, so there's no single tilt which will eliminate the problem. Likewise, during the takeoff roll the required lateral force will increase with velocity. So you can't just tilt the wheel/joystick at a certain angle and hold it there while taking off. You have to constantly adjust it as your velocity increases.

If a plane has to make a no-flaps emergency landing at 200 knots (which also happened to be about the regular takeoff speed of Concorde), now you're talking a lateral force of 7.06 m/s^2, or 0.72g. Which brings us to why runways are straight in the first place. It's not because it's easier to design and build. It's because it's a stable travel path. If for whatever reason during takeoff or landing the plane's controls stop working, the plane will want to go straight. Making the runway straight means the plane naturally (and with a little luck) will stay on the runway. Making the runway round means if you lose that lateral force being applied by your control surfaces for whatever reason, the plane is guaranteed to depart the runway at speed.

Comment Other usages that are changing (Score 3, Interesting) 237

Other shifts I've noticed in general vernacular over the last 30 years:
  • Less vs. fewer. Countable items are supposed to use 'fewer' ("10 items or fewer"). Non-countable items are supposed to use 'less' ("less water"). But nowadays I hardly ever see 'fewer' being used. Nearly everyone uses 'less' for both cases.
  • "and I" vs "and me". When I was young, the common error was to use "and me" when you were supposed to use "and I". e.g. "My wife and me went to the party" is incorrect. "My wife and I went to the party" is correct. The frequent correction by grammar nazis caused people to overcompensate, and now they say "and I" even when they're supposed to use "and me." e.g. "The dog sat by my wife and I" is incorrect. "The dog sat by my wife and me" is correct. A quick way to test is to eliminate the conjunction. "The dog sat by I" is clearly wrong, while "The dog sat by me" is right. So in this case you're supposed to use "and me".
  • Who vs whom. As with "and I" vs "and me" above, who is a subject, whom is an object. But almost everyone uses 'who' for both subject and object now.

BTW, my solution to "he or she" in writing was to simply add a slash - "s/he". One extra character and the same number of characters as "they". Unfortunately there's no way to pronounce it, so when speaking I usually use "they".

Don't even get me started on the silly rules about punctuation inside or outside quotation marks, which prioritize conformity over meaning.

Comment Re:Sucked out of an airplane? Not likely (Score 4, Informative) 272

Mythbusters tested a small bullet hole in a pressurized fuselage. The thing about pressure is it's a force per unit of area. So the larger the opening, the larger the forces involved (until the pressure is equalized). So something as small as a bullet hole doesn't result in large forces.

Aloha Airlines flight 243 lost the forward section of its fuselage. The flight attendant standing in row 2 near the front of the failed section was hit in the head by debris and fell to the floor. The flight attendant standing in row 5 near the rear of the failed section, with all the force of the cabin air behind her, was blown out by the decompression.

Airline fuselages are designed to suffer decompression only in a small section. You literally design weak sections surrounded by a lattice of strong sections, so a crack or failure cannot unzip the skin around the entire plane as it did in Aloha 243. The failure aboard Aloha is suspected to have started on the left side (one of the passengers noticed a crack by the door while boarding). And the theory is the crack failed producing a small hole. The flight attendant was blown towards the hole by outrushing air, and her body momentarily plugged the initial hole. This caused a pressure hammer from the air behind her rushing forward towards that hole blew out the entire forward cabin overhead.

Comment I concur I saw a similar effect (Score 1) 356

Not only if you put a lot of people from Muslim country concentrated in the same place their culture will tend to dominate, but my (french catholic) family living in a dominant Muslim area of France (banlieue of Paris with HLM) was influenced back by the culture. We ate couscous with merguez , and in fact sometimes my mother was saying "Inch'Allah" in place of the equivalent french expression. We were all born in other palce... But after living there 20 years some aspect imprinted onto us. I don't find that negative either to be frank, I am happy I had aspect of the muslim culture imprinted onto me.

Comment Yes you do (Score 1) 337

You're assuming the charge here for is a failed upgrade. The charge is for a failed forced upgrade. If Microsoft had informed users with a list of new features, what would happen in the upgrade process, and a disclaimer outlining the risks present in any upgrade, I think they would've been ok.

But they didn't do that. They did nearly everything they could to force the Win 10 upgrade down people's throats, including misclassifying it as a security update, constantly pestering people who had already said they didn't want the upgrade, and breaking long-established UI paradigms like clicking the X to dismiss a dialog, to make it the same as clicking OK. Once you inadvertently authorized the upgrade, the computer would often upgrade on its own overnight without user intervention. No information, no disclaimers. If that's how you're going to treat your users, then you deserve to be fully liable for all the problems your shenanigans cause.

OSS is fine because using it is completely voluntary. An OSS project might get into trouble if, say, Ubuntu forcibly upgraded pre-existing Ubuntu systems using sysv init to systemd. But no OSS project would be crazy enough to try that with pre-existing systems. The only reason Microsoft did it was because they knew software lock-in would prevent most users frustrated by their shenanigans from fleeing to a different OS.

Comment Re:Incoming (Score 1) 269

None of this is significant in terms of being any kind of a showstopper, in my estimation as an engineer. Yes, there are lots of things to cover in such an undertaking. No, none of the ones you mention are expected to pose significant problems.

Adequate power systems (power to weight, and charge issues) and the highest level management software are the only two hurdles really still a distance away. The former looks like it's going to fall within a year or two, the latter I give ten years, max.

Comment Re:Incoming (Score 1) 269

I didn't say a word about drones, if by drones, you mean quadcopters and the like.

As for robots, your thinking is too constrained. There are lots of design options that will handle snow just fine (and every other kind of terrain) that don't involve tires. Spider legs, for instance.

Vandalism: easily vandalized robots are counter indicated, obviously. Likewise robots that don't record what's happening to them. These are trivial engineering issues in the sense that solutions are readily available. They're no significant impediment to robot deliveries.

Fraud: One obvious solution is payment before delivery. Another, for payment on-site, is the same tech, or related tech, to that which lets a soda machine know you actually fed it dollar bills, before allowing access to the cargo. This isn't even a problem requiring solution before proceeding -- otherwise there would be no delivery now, and that's obviously not the case.

The only tech that really needs to happen that we don't quite have yet is the smarts to run the robot, and we're a little short on power systems, too. But we're very, very close. Solve those, get the cost down to where it needs to be, integrate available tech, and done.

Comment Tracking (Score 2) 269

I have a statement every month that tells me what and where I've spent my money. I can also use those purchases to show where I was at at the time if need be.

Mmm-hmm. Well, if you can't keep track of your spending, I suppose that'd be a reason to want to have others do it for you. I don't have that problem, personally, so it's difficult for me to emphasize with your use case. As for needing to show where you were... who do you need to show this to? The very fact that you think you need to show it to someone is worrisome, and speaks more to the problem than any solution.

Why would you worry about your purchases being tracked?

Because the government thinks it's perfectly okay to directly violate the constitution that authorizes its existence, that's why. Because the government is trying to look at the people's persons, houses, papers and effects without warrants, that's why. Because the government will, if given a chance, interfere with personal and consensual choices it has absolutely no ethical reason to concern itself with, that's why. Because the government runs a system of unjust gulags, driven by a manifestly corrupt legal system, which one should avoid with great care, that's why.

Comment Servicability (Score 1) 269

Sooner or later we'll give homes easily serviceable plumbing under raised flooring

That's exactly how I designed the plumbing in my home. You can get at every inch of plumbing, and where it transits a wall or floor, you can unhook it and pull it right through if you need to. The only in-wall plumbing in the entire home is for the shower, and the shower was emplaced on the back face of the wall the refrigerator is pulled up to; pull the refrigerator out, and you're looking directly at an open wall face containing the shower plumbing, just stick a wrench on it and do what you need to do. All sink plumbing and toilet plumbing is direct to the basement through the floors, and presents zero access challenge for service.

I did the electricity in a similar manner; it was even easier to design, due to the physical flexibility of the wiring and its relatively lower demands on space.

Houses don't have to be designed to have difficult to access utilities. Likewise a lot of other conventional approaches can be improved, such as insulation, wall thickness, concrete grades, mutability of internal space. If you ever get a chance to put a home together, it's entirely worth your time to think about things like these before agreeing to anyone's plans.

Slashdot Top Deals

"There is no distinctly American criminal class except Congress." -- Mark Twain